Modeling subauroral polarization streams equatorward of the plasmapause footprints

We report on a modeling study on the effects of subauroral polarization stream (SAPS) events equatorward of the plasmapause footprints, using the Sheffield Coupled Thermosphere-Ionosphere-Plasmasphere (CTIP) model. SAPS events are simulated by imposing a poleward electric field for 2 hours in the premidnight sector between 50° and 60° magnetic latitude. The presence of the SAPS results in a decrease in vertical total electron count and F region ion density, while the height of the F region can rise by up to 100 km. A study of the relative importance of the physical processes finds that the most significant contribution is the temperature increase due to ion-neutral friction, resulting in increased reaction rates of O+ loss. The recovery time for the SAPS studied is up to 10 hours